1. Field
The present invention relates to a method and apparatus for determining a type/architecture of a disk loaded on an optical disk drive.
2. Description of the Related Art
Optical disks, which are used as recording media of optical disk drives, can be classified as compact discs (CDs), digital versatile discs (DVDs), and next-generation discs such as Blue-ray discs (BDs). Data is recorded to and reproduced from BDs using a blue laser having a short wavelength, and thus BDs have a drastically increased storage capacity compared with DVDs. Recently, research into two-layered BDs and optical disk drives using the same has been actively conducted in order to further increase the data storage capacity of BDs.
In order to record data to or reproduce data from various types of optical disks, an optical disk drive needs to generate laser beams having different wavelengths according to the types of disks loaded thereon. In addition, a variety of parameter values for use in signal processing performed by optical disk drives needs to be set to adapt to the types of disks loaded on the optical disk drives.
Accordingly, every time a disk is loaded on an optical disk drive, the type of loaded disk needs to be determined.
Korean Patent Publication No. 1998-28839 discloses a technique of determining the type of disk. In Korean Patent Publication No. 1998-28839, the type of loaded disk is determined according to the length of time during which an S wave of a focus error signal appears, and single-layered disks and multi-layered disks can be discriminated from each other according to the number of S waves of the focus error signal.
However, when spherical aberration is a significant factor in optical disk drives, a small S wave for each recording layer is generated according to the amount of correction of the spherical aberration and accordingly can not be distinguished from noise. Thus, sometimes, an existing algorithm cannot handle this case. When noise is generated in a focus error signal due to, for example, vibrations or external disturbances when an actuator is driven for focus servo control, the noise may be misinterpreted as an S wave of the focus error signal. Therefore, a single-layered disk and a multi-layered disk may be wrongly discriminated from each other.